Species composition of the biospere



  • Intricate webs of interacting organisms
    • 2,000,000 species are known
    • 18,000 plants & animals discovered per year
    • estimated 87% of Eukaryotas unknown


  • Reflects billions of ways organisms have adapted, over and over, to a changing planet


  • Humans have altered 75% of ice-free surface
    • alters species composition

“Lines of the geography of plants” by Humboldt, 1817


Species are spatially arranged


Species are spatially arranged


Similar biological communities reside within our biomes


Climate drives broad distribution of terrestrial biomes


Biomes have distinct soil types


Species distribution varies within biomes


Seasons can impact species distribution


Migration can cross many biomes: Birds


Species may also be adapted for seasonal habitats


Niches define the limiting factors for a species


Tolerance Range: Coral Reefs


Ecological niches exist in n-dimensions


Distribution within biological communities


Species distributions are related to their niche space

Niches often overlap for different species


Ranges versus distribution: Crocodile


Ranges versus distribution: Plants


Species distributions: Coconut tree


Biogeography and species ranges: Alfred Wallace 1859


Zoogeographic regions: Wallace


Global change: climate refugia (Polar bear)


Global change: Range shifts of plants


Global change: Range expansion


Species distributions: Human impacts